The Case Comprehensive Cancer Center (Case CCC) Cytometry & Microscopy Core provides flow cytometry; cell sorting; imaging flow cytometry; laser scanning cytometry; laser scanning / high resolution / two-photon confocal microscopy; TURF; digital video microscopy; and imaging fluorescence microscopy to investigators at Case Western Reserve University (CWRU) and other institutions in the wider Cleveland area. The cytometry core was created in 1985 and has been continuously funded by NCI the P30 mechanism since 1987. The Core has cooperative agreements with the Case Center for Aids Research (CFAR) and the Lerner Institute, leveraging expertise, providing wider access to equipment, and enabling joint planning and decision-making. More than 150 principal investigators access Core services per ~5 year period. The average number of laboratories accessing in a given year is >100. The core houses three flow cytometers - BD Biosciences LSR I and LSR II and a Beckman Coulter XL. We acquired the XL in 1999 with institutional funds; the LSR I in 2001 with funds from the Fannie Ripple Foundation, and the LSR II in 2003 with funds from NIH S10 grant RR015967. The XL and the LSR I are no longer supported by the manufacturer, dysfunctional, and very difficult to maintain. Parts are hard to find and breakdowns are frequent. The LSR I has been disabled since 2012 and the XL has not been repaired after laser failure in April, 2015. Therefore, we have only one modern, multi-laser flow cytometer (LSR II). This creates scheduling conflicts and over-capacity run-time difficulties. During periods of overflow, we shift investigators to the CFAR Immune Function Core Fortessa or send investigators to the Lerner Institute's Flow Cytometry and Imaging Core, but for most investigators both our LSR II and the CFAR Fortessa are not the appropriate instrument, and both instruments are heavily subscribed. The Lerner Institute Core is also heavily used and unable to absorb the over-flow. Therefore, we are requesting funds to purchase an intermediate Attune Nxt flow cytometer with acoustic focusing, which will relieve work-flow stress on the LSR II, provide a low cost LSR II alternative, provide high quality no-wash assays that will reduce sample preparation labor, and enable higher flow rates for DNA content, providing cost saving benefits to all users.